We revisit the derivation of the apparatus-dependent correction to the energy levels of quantum cyclotron states, as previously outlined [Boulware et al., Phys. Rev. D 32, 729 (1985)]. We evaluate the leading corrections to the axial, magnetron, cyclotron, and spin-projection-dependent energy levels due to the altered photon field quantization in the vicinity of a conducting wall. Our work significantly extends previous considerations. Quantum cyclotron states are used for the determination of the electron $g$ factor in Penning traps. Our calculations show that the numerically largest apparatus-dependent corrections can be expected for the axial and magnetron frequencies, where they can be as large as ${10}^{-8}$ in relative units. For the cyclotron frequency, one can expect corrections on the order of ${10}^{-12}$, which can affect the determination of the anomalous magnetic moment of the electron.

In 2004 the matrix element method was used in a pioneering work by the Tevatron experiment $D\cancel{0}$ to determine the top-quark mass from a handful of events. Since then the method has matured into a powerful analysis tool. While the first applications were restricted to leading-order accuracy, the extension to next-to-leading order (NLO) accuracy has also been studied. In this article we explore the potential of the matrix element method at NLO to determine the top-quark mass using events with pair-produced top quarks. We simulate a toy experiment by generating unweighted events with a fixed input mass and apply the matrix element method to construct an estimator for the top-quark mass. Two different setups are investigated; unweighted events obtained from the fixed-order cross section at NLO accuracy as well as events obtained using POWHEG matched to a parton shower. The latter lead to a more realistic simulation and allow to study the impact of higher-order corrections as well as the robustness of the approach. We find that the matrix element method in NLO accuracy leads to a significant reduction of the theoretical uncertainties compared to leading order. In view of the high-luminosity phase of the LHC, this observation is especially relevant in analyses which are no longer dominated by statistical uncertainties.

We investigate the $\mathcal{R}(D)$ and $\mathcal{R}(D^{*})$ anomalies in the context of the $B-L$ extension of the minimal supersymmetric Standard Model with inverse seesaw. We demonstrate that the lepton penguin $W^{\pm }l{\overline{\nu }}_l$ ($l=e$, $\mu$, $\tau$) mediated by $CP$-even/odd right-handed sneutrinos, charginos, and neutralinos can account for these anomalies simultaneously.

Dark matter (DM) nature is one of the major issues in physics. The search for a DM candidate has motivated the known proposal of an ultralight scalar field (ULSF). We explore the possibility to search for this ULSF at the upcoming European Spallation Source neutrino Super-Beam experiment. We have considered the recent study case in which there could be an interaction between the ULSF and active neutrinos. We have found that in this future experimental setup, the sensitivity is competitive with other neutrino physics experiments. We show the expected future sensitivity for the main parameter modeling the interaction between ULSF and neutrinos.

We present perspectives for searching for light dark matter production mediated by a leptophilic scalar $\varphi$ and a dark photon $A^{\prime }$ in experiments at a super c-tau factory. Based on the analysis of the associative production of mediators and $\tau$-leptons at the energies of a future collider, the possibility of searching in the nonexcluded region of the parameter space was found. The obtained sensitivity curves at the 90% C.L. for the mediators’ mass range below 4 GeV demonstrate the power of the super c-tau factory for light dark matter search.

We present a study of lattice-QCD methods to determine the relevant hadronic form factors for radiative-leptonic decays of pseudoscalar mesons. We provide numerical results for $D_s^{+}\to {\ell }^{+}\nu \gamma$. Our calculation is performed using a domain-wall action for all quark flavors and on a single RBC/UKQCD lattice gauge-field ensemble. The first part of the study is how to best control two sources of systematic error inherent in the calculation, specifically the unwanted excited states created by the meson interpolating field and unwanted exponentials in the sum over intermediate states. Using a 3D sequential propagator allows for better control over unwanted exponentials from intermediate states, while using a 4D sequential propagator allows for better control over excited states. We perform individual analyses of the 3D and 4D methods, as well as a combined analysis using both methods, and find that the 3D sequential propagator offers good control over both sources of systematic uncertainties for the smallest number of propagator solves. From there, we further improve the use of a 3D sequential propagator by employing an infinite-volume approximation method, which allows us to calculate the relevant form factors over the entire allowed range of photon energies. We then study improvements gained by performing the calculation using a different three-point function, using ratios of three-point functions, averaging over positive and negative photon momentum, and using an improved method for extracting the structure-dependent part of the axial form factor. The optimal combination of methods yields results for the $D_s^{+}\to {\ell }^{+}\nu \gamma$ structure-dependent vector and axial form factors in the entire kinematic range with statistical plus fitting uncertainties of order 5%, using 25 gauge configurations with 64 samples per configuration.

We present a lattice determination of the leading-order hadronic vacuum polarization (HVP) contribution to the muon anomalous magnetic moment, $a_{\mu }^{\mathrm{HVP}}$, in the so-called short and intermediate time-distance windows, $a_{\mu }^{\mathrm{SD}}$ and $a_{\mu }^{\mathrm{W}}$, defined by the RBC/UKQCD Collaboration [Phys. Rev. Lett. 121, 022003 (2018)]. We employ gauge ensembles produced by the Extended Twisted Mass Collaboration (ETMC) with $N_f=2+1+1$ flavors of Wilson-clover twisted-mass quarks with masses of all the dynamical quark flavors tuned close to their physical values. The simulations are carried out at three values of the lattice spacing equal to $\simeq 0.057$, 0.068 and 0.080 fm with spatial lattice sizes up to $L\simeq 7.6\mathrm{fm}$. For the short-distance window we obtain $a_{\mu }^{\mathrm{SD}}(\mathrm{ETMC})=69.27(34)\times {10}^{-10}$, which is consistent with the recent dispersive value of $a_{\mu }^{\mathrm{SD}}(e^{+}{e}^{-})=68.4(5)\times {10}^{-10}$ [, Phys. Lett. B 833, 137313 (2022)]. In the case of the intermediate window we get the value $a_{\mu }^{\mathrm{W}}(\mathrm{ETMC})=236.3(1.3)\times {10}^{-10}$, which is consistent with the result $a_{\mu }^{\mathrm{W}}(\mathrm{BMW})=236.7(1.4)\times {10}^{-10}$ [, Nature (London) 593, 51 (2021)] by the BMW Collaboration as well as with the recent determination by the CLS/Mainz group of $a_{\mu }^{\mathrm{W}}(\mathrm{CLS})=237.30(1.46)\times {10}^{-10}$ [, Phys. Rev. D 106, 114502 (2022)]. However, it is larger than the dispersive result of $a_{\mu }^{\mathrm{W}}(e^{+}{e}^{-})=229.4(1.4)\times {10}^{-10}$ by approximately 3.6 standard deviations. The tension increases to approximately 4.5 standard deviations if we average our ETMC result with those by BMW and CLS/Mainz. Our accurate lattice results in the short and intermediate windows point to a possible deviation of the $e^{+}{e}^{-}$ cross section data with respect to Standard Model predictions in the low- and intermediate-energy regions but not in the high-energy region.

The LHCb collaboration has detected a new hidden-charm pentaquark with the quantum numbers of a $\mathrm{\Lambda }$ baryon: the $P_{\psi s}^{\mathrm{\Lambda }}(4338)$. This pentaquark will be interpreted as a ${\overline{D}}_s{\mathrm{\Lambda }}_c-\overline{D}{\mathrm{\Xi }}_c$ resonance within a contact-range theory. Here we briefly comment on the relation of the new $P_{\psi s}^{\mathrm{\Lambda }}(4338)$ with the $P_{\psi s}^{\mathrm{\Lambda }}(4459)$. We find that the $P_{\psi s}^{\mathrm{\Lambda }}(4338)$ and $P_{\psi s}^{\mathrm{\Lambda }}(4459)$ both accept a common description in terms of the same parameters, which predicts the existence of a few additional $P_{\psi }^N$, $P_{\psi s}^{\mathrm{\Lambda }}$, $P_{\psi s}^{\mathrm{\Sigma }}$, and $P_{\psi ss}^{\mathrm{\Xi }}$ molecular pentaquarks composed of a charmed antimeson and an antitriplet charmed baryon. The most robust of these predicted pentaquarks is a $P_{\psi s}^{\mathrm{\Lambda }}$ with a mass in the $(4235–4255)\mathrm{MeV}$ range, while other two interesting ones are a $P_{\psi }^N(4150)$ and a $P_{\psi s}^{\mathrm{\Sigma }}(4335)$, the latter basically at the same mass as the $P_{\psi s}^{\mathrm{\Lambda }}(4338)$, with which it might mix owing to isospin symmetry breaking effects.

In this work, we raise a novel method for searching for the ${\mathrm{\Xi }}_c^{0+}\text{−}{\mathrm{\Xi }}_c^{0+\prime }$ mixing effect in an angular distribution analysis of the ${\mathrm{\Xi }}_c\to {\mathrm{\Xi }}^{(\prime )}(\mathrm{\Lambda }\pi ){\ell }^{+}\nu$ decay, where the mixing effect can be observed by the appearance of the ${\mathrm{\Xi }}^{\prime }$ resonance. Armed with this angular distribution, the branching fraction and the forward-backward asymmetry are predicted. We point out that the forward-backward asymmetry, as a function of the invariant mass square of ${\mathrm{\Xi }}^{(\prime )}$ and the ${\mathrm{\Xi }}_c^{0+}\text{−}{\mathrm{\Xi }}_c^{0+\prime }$ mixing angle ${\theta }_c$, can be used to distinguish the two resonances ${\mathrm{\Xi }}^{(\prime )}$ and even provide a possibility to determine the exact mixing angle.

Study of the transverse structure of the proton is one of the major physics goals of the upcoming electron ion collider (EIC). The gluon transverse momentum dependent distributions (TMDs) form an essential focus of this effort and are important towards understanding the angular momentum contribution to proton spin as well as QCD factorization. However, very limited experimental constraints on the gluon TMDs exist currently. As the heavy quark production in lepton-nucleon DIS gets a dominant contribution from the photon-gluon-fusion process, heavy quark production makes an attractive tool to probe gluon distributions in nucleons. In this paper we present a study of heavy flavor hadron pair reconstruction at a future EIC detector with MAPS based inner tracking and vertexing subsystems to constrain gluon TMDs. We utilize the excellent track pointing resolution provided by the detector to exclusively reconstruct heavy flavor hadron pairs via their hadronic decay channels and also to develop a heavy flavor hadron tagging algorithm. Statistical uncertainty projections on azimuthal asymmetries corresponding to gluon TMDs at the EIC is evaluated. The heavy flavor tagging is found to substantially enhance the purity of heavy flavor hadron pair selection, and the statistical precision of the measurement compared to that from exclusive reconstruction. The correlation between the azimuthal angle of the transverse momentum of the gluon initiating the process and that of the corresponding heavy flavor hadron pair was also studied and found to be well correlated. This study opens up heavy flavor hadron pair measurements as an attractive channel to access gluon TMDs at the EIC.

In this paper, we present an improved parametrization of the elastic scattering of spin-0 particles, which is based on a dispersive representation for the inverse scattering amplitude. Besides being based on well-known general principles, the requirement that the inverse amplitude should satisfy the dispersion relation significantly constrains its possible forms and have not been incorporated in the existing parametrizations so far. While the right-hand cut of the inverse scattering amplitude is controlled by unitarity, the contribution from the left-hand cut, which comes from the crossing symmetry, is commonly ignored or incorporated improperly. The latter is parametrized using the expansion in a suitably constructed conformal variable, which accounts for its analytic structure. The correct implementations of the Adler zero and threshold factors for angular momentum $J>0$ are discussed in detail as well. The amplitudes are written in a compact analytic form and provide a useful tool to analyze current and future lattice data in the elastic region improving upon the commonly used Breit-Wigner or K-matrix approaches.

We report a measurement of the strange axial coupling constant $g_A^s$ using atmospheric neutrino data at KamLAND. This constant is a component of the axial form factor of the neutral-current quasielastic (NCQE) interaction. The value of $g_A^s$ significantly changes the ratio of proton and neutron NCQE cross sections. KamLAND is suitable for measuring NCQE interactions as it can detect nucleon recoils with low-energy thresholds and measure neutron multiplicity with high efficiency. KamLAND data, including the information on neutron multiplicity associated with the NCQE interactions, makes it possible to measure $g_A^s$ with a suppressed dependence on the axial mass $M_A$, which has not yet been determined. For a comprehensive prediction of the neutron emission associated with neutrino interactions, we establish a simulation of particle emission via nuclear deexcitation of ${}^{12}\mathrm{C}$, a process not considered in existing neutrino Monte Carlo event generators. Energy spectrum fitting for each neutron multiplicity gives $g_A^s=-0.14_{-0.26}^{+0.25}$, which is the most stringent limit obtained using NCQE interactions without $M_A$ constraints. The two-body current contribution considered in this analysis relies on a theoretically effective model and electron scattering experiments and requires future verification by direct measurements and future model improvement.

We propose studying the structure of the ${\chi }_{c1}(3872)$ axial vector meson through its ${\gamma }_L^{*}\gamma \to {\chi }_{c1}(3872)$ transition form factor. We derive a light-front wave function representation of the form factor for the lowest $c\overline{c}$ Fock state. We found that the reduced width of the state is well within the current experimental bound recently published by the Belle Collaboration. This strongly suggests a crucial role of the $c\overline{c}$ Fock-state in the photon-induced production. Our results for the $Q^2$ dependence can be tested by future single-tagged $e^{+}{e}^{-}$ experiments, giving further insight into the short-distance structure of this meson.

We show that the quantization ambiguities of loop quantum cosmology, when considered in wider generality, can be used to produce discretionary dynamical behavior. There is an infinite dimensional space of ambiguities which parallels the infinite list of higher curvature corrections in perturbative quantum gravity. There is, however, an ensemble of qualitative consequences which are generic in the sense that they are independent of these ambiguities. Among these, one has well-defined fundamental dynamics across the big bang, as well as extra microscopic quantum degrees of freedom that might be relevant in discussions about unitarity in quantum gravity. We show that, in addition to the well-known bouncing solutions of the effective equations, there are other generic types of solutions for sufficiently soft initial conditions in the matter sector (tunneling solutions) where the scale factor goes through zero and the spacetime orientation is inverted. We also show that, generically, a contracting semiclassical universe branches off at the big bang into a quantum superposition of universes with different quantum numbers. Despite their lack of quantitative predictive power, these models offer a fertile playground for the discussion of qualitative and conceptual issues in quantum gravity.

We study the properties of 10D multiple D0-brane (mD0) system described by a recently proposed complete supersymmetric and $\kappa$-symmetric nonlinear action which includes an arbitrary positive definite function $\mathcal{M}(\mathcal{H})$ of the relative motion Hamiltonian $\mathcal{H}$. First we show how the action with a particular nonlinear $\mathcal{M}(\mathcal{H})$ can be obtained from the action for 11D multiple M-wave (multiple M0-brane or mM0) system. Then we obtain the complete set of equations of motion of mD0 system with arbitrary positive definite $\mathcal{M}(\mathcal{H})$, perform a convenient gauge fixing, solve the center of energy equations and establish an interesting correspondence between the relative motion mD0 equations and the equations of maximally supersymmetric $\mathrm{SU}(N)$ Yang-Mills theory (SYM). We show that this correspondence does not imply a gauge equivalence but establishes a relation between solutions of the system. In particular, it implies that all the supersymmetric solutions of mD0 equations in its relative motion part coincide with supersymmetric solutions of the SYM equations.

Energy conservation has the status of a fundamental physical principle. However, measurements in quantum mechanics do not comply with energy conservation. Therefore, it is expected that a more fundamental theory of gravity—one that is less incompatible with quantum mechanics—should admit energy nonconservations. This paper begins by identifying the conditions for a theory to have an energy-momentum tensor that is not conserved. Then, the trajectory equation for pointlike particles that lose energy is derived, showing that energy nonconservation produces a particular acceleration. As an example, the unimodular theory of gravity is studied. Interestingly, in spherical symmetry, given that there is a generalized Birkhoff theorem and that the energy-momentum tensor divergence is a closed form, the trajectories of test particles that lose energy can be found using well-known methods. Finally, limits on the energy nonconservation parameters are set using Solar System observations.

We calculate the spectrum of quasinormal modes of slowly rotating Kerr-Newman black holes. Using a perturbative double expansion method, second order in rotation and first order in nonradial perturbations, we obtain the system of equations that describe polar-led and axial-led perturbations. We analyze gravitational, electromagnetic and scalar fundamental modes, focusing on the $\mathrm{l}=2$ perturbations. We reproduce previous results and check that isospectrality between axial and polar-led perturbations is approximately satisfied with good accuracy. Our results show that the slow rotation approximation can be used to estimate with reasonable precision the spectrum of configurations up to 50%–60% of the extremal angular momentum.

The worldline effective field theory (EFT) gives a gauge-invariant definition of black hole conservative tidal responses (Love numbers), dissipation numbers, and their spin-0 and spin-1 analogs. In the first part of this paper we show how the EFT allows us to circumvent the source/response ambiguity without having to use the analytic continuation prescription. The source/response ambiguity appears if relativistic corrections to external sources overlap with the response. However, these corrections can be clearly identified and isolated using the EFT. We illustrate that by explicitly computing static one-point functions of various external fields perturbing the four-dimensional Schwarzschild geometry. Upon resumming all relevant Feynman diagrams, we find that the relativistic terms that may mimic the response actually vanish for static black holes. Thus, the extraction of Love numbers from matching the EFT and general relativity (GR) calculations is completely unambiguous, and it confirms previous results that the Love numbers vanish identically for all types of perturbations. We also study in detail another type of fine-tuning in the EFT, the absence of Love numbers’ running. We show that logarithmic corrections to Love numbers do stem from individual loop diagrams in generic gauges, but cancel after all diagrams are summed over. In the particular cases of spin-0 and spin-2 fields the logarithms are completely absent if one uses the Kaluza-Klein metric decomposition. In the second part of the paper we compute frequency-dependent dissipative response contributions to the one-point functions using the Schwinger-Keldysh formalism. We extract black hole dissipation numbers by comparing the one-point functions in the EFT and GR. Our results are in perfect agreement with those obtained from a manifestly gauge-invariant matching of absorption cross sections.

We propose a novel mechanism for significantly enhancing the amplitude of primordial electromagnetic fields during inflation. Similar to existing proposals, our idea is based on parametric resonance effects due to conformal-symmetry-breaking coupling of a gauge field and the inflaton. Our proposed scenario, however, significantly differs from previously studied models and avoids their shortcomings. We, particularly, construct a viable system where the gauge field is exponentially amplified on super-horizon scales, therefore evading the no-go theorem formulated on the basis of widely encountered drastic backreaction of the magnetic field energy on the inflationary background. We argue that in order for the resonant scenario to work with a bounded and positive-definite coupling function, a mass term for the gauge sector is required. We compute the spectrum of the produced magnetic fields and demonstrate the compatibility with current observational constraints. We demonstrate that while the magnetic fields do not noticeably backreact on the inflationary background, the nonzero mass term can contribute significantly to the total energy-momentum tensor. We point out the parameter space where the latter issue is absent.

We study the response function of the Einstein Telescope to kinematic Doppler anisotropies, which represent one of the guaranteed properties of the stochastic gravitational wave background. If the frequency dependence of the stochastic background changes slope within the detector frequency band, the Doppler anisotropic contribution to the signal can not be factorized in a part depending on frequency, and a part depending on direction. For the first time, we study the detector response function to Doppler anisotropies without making any factorizable Ansatz. Moreover, we do not assume that kinematic effects are small, and we derive general formulas valid for any relative velocity among frames. We apply our findings to three well-motivated examples of background profiles; power-law, broken power-law, and models with a resonance motivated by primordial black hole scenarios. We derive the signal-to-noise ratio associated with an optimal estimator for the detection of nonfactorizable kinematic anisotropies, and we study it for representative examples.